Back fire preventer



Aug. 16, 1932. w. H. VAN HORN 1,872,368

BACK FIRE PREVENTER Filed Sept. 25, 1950 Jmxmto Patented Aug. ,1-6, 31932 UNITED ,zsmrs-s WILIIAM H. VAN HORN; OF BAIJTIMQ.BE,;MARYLAND, 'ASSIGNOR I'O THE I. C.'-I. KEEP MANUFACTURING COMPANY, 01F BAI4'TIMORE, MARYLAND, A CORPOBA'IION' OI mmim nacxrmn- PBEVENTEB Application filed September1E8, 1930. 'Serial No. 488,954.

The present invention relates to back-fire preventers, and is designed particularly to take care of a pipe line or main .which conveys gaseous fuel from they point of genera- .5 tion or mixing to the point of consumption or burning.

It has for its object to guard againstthe danger of accidental ignition of the gas on the burner side and the running back of the flame to the generating or mixing plant.

In the drawing herewith, I have illustrated one form of the invention, in order that the same may be clear to those skilled in the art, but it will be understood that this is illus- 15 trative, and that mechanical variations may be made which are within the purview of my invention.

Referring to the drawing, indicates'the inlet side of the device, designed to be 20 coupled in any suitable'manner with apipe line leading from the gasgenerator or mixer.

A valve casing 11 is provided, having a valve seat 12 fora valve 13 normally urged toits seat by a spring 14, the valve=stein15at its 25 lower end engaging a recess inthe bottom plate 16 of the valve casing, whileitsupper end engages a recess in a capplate 17 so asto guide and steady the movements of the valve toward and from its-seat.

The valve stem is provided with a projection 18, here shown inthe form of a disk, which is engaged by a tappet' arm 19 mounted on a shaft 20 in suitable' bearings within the casing, the end of the shaft 20 projecting through a wall of thevalve casing and having fixed thereto the arm 21, the upper end of which is linked in any suitable manner by a loose linkage connection, here shown as made up of members 22 and 23, to a latch or trip member 24 pivotally mounted on acap plate 25 carried by the elbow 26, to which elbow is connected the outlet 27, which, by any suitable piping arrangement, communicates with the burners or other point of consumption. 1

From the valve casing, the gas, the course of which is indicated by the arrows, flows to the section 28, which is'prci'erably eulargod at the point 29,- as shown, to give 50 proper area for the flow ofgas, and the gas ing 30, and providedwith any suitable flame T and cap 25, which cap is provided with a should occur, its course would be 'through the then, passes downwardly into a closedchamber 30,,the walls of whichrare providedrwith any suitable number of nipples 31,'ithreaded or otherwise secured in the walls of the easinterrupting means, such as gauze, which will permit the flowot gas therethrough, but will effectively check the assage offiame.

The gas, coming throug 'thenipples 31, passesto the casing 32, and 'enters't-he open lower end of the ipe'33 which passes through theobottom of t e'casing'30 to a'pointremoved from the bottom'34 ofthe outer casing 32. The gas will then pass up the'pipe 33, through the section; 28 -'to the'elbow26,

and thence'to the outlet 2 Bottom 34: is vcurvedupwardly, as shown, and tends'to direct gas from'the nipples 31 centrally ofthe casing, 32 andfdirectly to the openvlower end ofthe pipe-33. Secured to the bottom is'a fusible and frangible connection 35,,from whicha-w'ire 36leads upwardlyrthroug'h the pipe 33, section 28, elbow 26,

suitable stufiing box 37, and engagesthe arm '38 of the trip member 24, wire 36, at its upper vend being suitably secured to the arm In operation of the device if a back-fire elbow 26, down the ipe 33, and directly againstithe thin meta bottom 34. The action of'thefiame or the pressure'will destroy the coupling and bulge the bottom 34 downwardly. That is, the effect of either heat or :pressure will be to .release the wire 36, freeing the trip .24 and permitting the spring-14 to at once close the valve 15 by The device constitutes a very efiectual preventer of back-firing, ensuring not only a prompt closing of the valve, but so controlling and directing any back-tire as to prevent its reaching either the inlet side of the line or even the fuel which may be in the chambers and passages of the device itself. The back-fire effect is confined at the elbow 26, the pipe 33, and the outer casing 32.

The action of the device is such that no damage can result to any part of the apparatus, except the thin metal bottom 34 and the breakable coupling 35.

The replacement of the device after backfire explosion is, of course, simple, for by renewing the connection 35 and restoring the bottom 34, or replacing the bottom 34, the other parts, including the trip 24, the rocker arm 21, and the tappet 19, may be reset, putting the valve 13 in its normally open position, with the spring 14 under stress. This is of particular value, for the reason that in some instances efiicient back-fire preventers are so injured or completely destroyed by back-firing that their repair, replacement, and resetting is not only expensive. but in volves very considerable delay before the pipe line can be again put into use.

lVhat is claimed is:

1. The combination" with gaseous fuel supply and delivery pipes, and a valve controlling flow through the supply pipe, of two casings arranged one within the other, the inner casing having an inlet connected with the supply pipe and an outlet opening into the outer casing, means for interrupting the passage of flame through the outlet of the inner casing, the outer casing havin a yielding wall and an outlet communicating with the delivery pipe, means acting to move the valve to closed position, and means for normally retaining the valve in open position and including a frangible connection with theyielding wall of the outer casing.

2. The combination with gaseous fuel suply and deliverypipes,-and a valve controlmg flow through the supply pipe, of two casings arranged one Within the other, the inner casing having an inlet connected with the supply pipe and having a plurality of outlets opening into the outer casing, means for interrupting the passage of flame through each of the outlets of the inner casing, the outer casing having a; yielding wall and an outlet communicating with the delivery pipe, means acting to move the valve to closed position, and means for normally retaining the valve in open position and including a frangible connection with the yielding wall of the outer casing.

3. The combination with gaseous fuel su ly and delivery pipes, and a valve contrdling flow through the supply pipe, of two casings arrangecl one within the other, the inner casing having at one end an inlet connected with the supply pipe and having formed in its side wall a plurality of outlets opening into the outer casing, means for interrupting the passage of flames through any of said outlets of the inner casing, a tube extending through the inner'casing and'conn ing the outer casing with the delivery p e, means acting to move the valve to closed position, and means for normally retaining the valve in open position extending through said tube and including a frangible'connection with a 'wall of the outer casing.

4. The combination with gaseous fuel supply and delivery pipes, and a valve controlling flow through the supply pipe, of two casings arranged one within the other, the inner casing having an inlet connected with the supply pipe and an outlet opening into the outer casing and the outer casing having an outlet communicating with the delivery pipe, a spring acting to move the valve to closed position, a pivotally mounted detent normally restraining movement of the valve under the action of the spring, and means adapted to release the detent in event of explosion in the delivery pipe or the connection between said pipe and the outer casing.

5. The combination with gaseous fuel supply and delivery pipes, and a valve control ling flow through the supply pipe, of two casings arranged one within the other, the inner casing having an inlet connected with the supply pipe and an outlet opening into the outer casing and the outer casing having an outlet communicating with the delivery pipe, a spring acting to move the valve to closed position, a pivotally mounted detent normallyrestraining movement of the valve under the action of the spring, and means, including a frangible connection within the outer casing, adapted to release the detent in event of explosion in the delivery pipe or the connection between such pipe and the outer casing.

6. The combination with gaseous fuel supply and delivery pipes, of a connection between said pipes including a casing having an inlet, at its upper .end, connected with the supply pipe, 8. second casing surrounding an outlet from and extending beneath the bottom of said casing, a tube extending through the bottom of the inner casing and connecting the interior of the outer casing with the delivery pipe, a valve in the supply pipe, a spring acting to close said valve,-a detent adapted to restrain movement of the valve under the action of the spring, and a connection between the detent and the inner face of the bottom of the outer casing including a frangible section, whereby in event of an explosion in the delivery pipe or outer casing the detent will be released.

7. The combination with gaseous fuel supply and delivery pipes, of a connection between said pipes including a casing having at its upper end an inlet connected with the supply pipe and having a series of tubular members extending through its side wall, a second casing surrounding all of said tubular members on and extending beneath the first said casing, means in each of said tubular members of the inner casing for preventing the passage of flame through said member, a tube extending through the bottom of the inner casing and connecting the interior of the outer casing with the delivery pipe, a valve in the supply pipe, a spring acting to close said valve, a detent adapted to restrain movement of the valve under the action of the spring, and a connection between the detent and the inner face of the bottom of the outer casing including a frangible section whereby in event of an explosion in the delivery pipe or outer casing be released.

8. The combination with gaseous fuel supply and delivery pipes, and a valve controlling flow through the supply pipe, of two casings arranged one within the other, the inner casing having an inlet connected with y the supply pipe and an outlet opening into the outer casing, means for interrupting the passage of flame through the outlet of the inner casing, the outer casing having a yielding wall and an outlet communicating with the detent will delivery ipe, means acting to'move the valve to close osition, and means for normally retaining iihe valve in open position extending through said tube and including a frangible "a whereof I have hereunto set my hand.

WILLIAM H. VAN HORN.

the delivery pipe, means acting to move the valve to closed position, and means for normally retaining the valve in open position and including a frangible connection with the yielding wall of the outer casing adapted to be destroyed by abnormally high temperatures.

9. The combination with gaseous fuel supply and delivery pipes, and a valve controlling fiow through the supply pipe, of two casings arranged one within the other, the inner casing having an inlet connected with the supply pipe and having a plurality of outlets opening into the outer casing, means for interrupting the passage of flame through each of the outlets of the inner casing, the outer casing having a yielding wall and an outlet communicating with the delivery pipe, means acting to move the valve to closed. position, and means for normally retaining the valve in open position and including a frangible connection with the yielding wall of the outer casing adapted to be destroyed by abnormally high temperatures.

10. The combination with gaseous fuel supply and delivery pipes, and a valve controlling flow through the supply pipe, of two casings arranged one within the other, the

. inner casing having at one end aninlet connected with the supply pipe and having formed in its side wall a plurality of out lets opening into the outer casing, means for interrupting the passage of flames through any of said outlets of the inner casing, a tube extending1 through the inner casing and connecting t e outer casing with the 

